1. Field of Invention
This invention relates to a drum used for transporting goods, and more particularly to a steel drum for containing material including liquid or semi-liquid materials which is reusable and/or recyclicable.
2. Description of Prior Art
Cylindrical containers such as steel drums have been used for a long time as a means of storing or transporting a variety of materials including powdery or granular solids, or liquids and semi-liquids. These containers are built to withstand the exigencies of transit. The materials stored in them are removed by first removing the top of the containers and then pouring or pumping the materials out.
Drums are sometimes used to store so-called semi-liquid materials such as adhesives, lubricants, hazardous material or other material that would contaminate or leave contaminants on the interior surface thereof. This may involve materials which are basically meltable plastics which may be poured therein. These materials solidify upon cooling. To remove the material one uses a machine with a plunger, which is heated and equipped with an "O" ring type of seal. After removing the top cover, and disc seal, the drum is ready for emptying the contents. As the plunger is pushed downwardly into the drum, the heater melts and liquifies the materials and as the plunger moves downwardly, the material is pumped out through the plunger and put into the manufacturing process.
When the plunger gets toward the bottom of the drum, there remains a small amount of material which cannot be pumped out but is left in the bottom of the container after the plunger heating system has been removed. Such drums are normally used once and then discarded since the interior has become contaminated with the material it contained. Disposal and even recycling of such drums because of this is difficult. It has become desirable to provide drums however that may be reused or subject to recycling.
Moreover, steel drums are typically made of a heavy gauge metal and are relatively expensive. In view of the shipped material contaminating the interior surface of the drum, reuse is not possible, recycling is difficult and disposal may require special handling.